The confinement of organic synthesis within waterborne nanoreactors is regarded with increasing attention to improve its yield and reduce the environmental impact. However, many catalysts, such as graphene, are barely dispersible in aqueous media and many chemical reactions cannot be performed in the presence of water due to thermodynamic limitations. Therefore, there is an urgent need to develop novel strategies to carry out these processes in more sustainable conditions. To pursue this goal, in this work, a waterborne supramolecular nanoreactor is developed. The system comprises a polymeric micelle obtained from the self‐assembly of pyrrole‐based amphiphilic block copolymers. The active catalytic component is represented by few graphene layers, functionalized with pyrrole to enhance their interaction with the micelle core and hence their nanoencapsulation. Using this nanoreactor, it is possible to synthesize imines starting from primary amines and aldehydes or ketones with high yield and in short time (Y = 90% after 5 min) at room temperature. Moreover, an efficient strategy to recycle the reactor is proposed, thus increasing the potential of this technology.
Edge functionalization of graphene layers is of great interest in the field of materials chemistry: the properties of graphene are substantially unaltered and its compatibility and chemical reactivity with various environments can be tuned. In this work, edge functionalization of graphene layers was performed with a 2-pyrone, ethyl 3-hydroxy-2-oxo-2H-pyran-6-carboxylate (Pyr-COOEt). 2-Pyrones are C-6 unsaturated heterocyclic sugar derivatives and are intriguing building blocks for the preparation of innovative chemical structures. Sodium 3-acetoxy-2-oxo-2Hpyran-6-carboxylate was prepared starting from mucic acid, in a one-pot synthesis with a yield of about 74%, and was then transformed into the acid and then into ethyl ester derivatives. The adduct of Pyr-COOEt with a high surface area graphite (HSAG) was obtained by simply mixing and donating energy, either thermal or mechanical. The functionalization yield was estimated from thermogravimetric analysis (TGA) data and was found to be up to 91%. The adducts were characterized by Fourier transform infrared and Raman spectroscopies and wide-angle X-ray diffraction. The presence of pyrone in the adduct was clearly detected in the IR spectra, and the bulk structure of the graphitic substrate was found to be substantially unaltered by the functionalization reaction. The experimental findings suggest that the edge functionalization of the graphene layers occurred. Stable water dispersions of HSAG/Pyr adducts were prepared and studied through ultraviolet−visible analysis. Aggregates of few-layer graphene were obtained by mild sonication and centrifugation, as revealed by high-resolution transmission electron microscopy. This paper shows that a biobased molecule can be used for selectively decorating the edges of graphene layers, with oxygenated functional groups having a defined chemical structure and avoiding the use of oil-based, dangerous, and even noxious ingredients. The most plausible interpretation for the formation of the HSAG adduct with 2-pyrone seems to be the cycloaddition reaction between the edges of the graphitic substrate and the unsaturated biomolecule. Such a functionalization appears to be suitable for a scale up and paves the way for the preparation of a variety of derivatives.
Inspired by decades of research in the compatibilization of fillers into elastomeric composites for high‐performance materials, a novel polyurethane‐based stretchable carbon ink is created by taking advantage of a Janus molecule, 2‐(2,5‐dimethyl‐1H‐pyrrol‐1‐yl)propane‐1,3‐diol (serinol pyrrole, SP). SP is used to functionalize the carbon and comonomer in the polymer phase. The use of SPs in both the organic and inorganic phases results in an improved interaction between the two phases. When printed, the functionalized material has a factor 1.5 lower resistance‐strain dependence when compared to its unfunctionalized analogue. This behavior is superior to commercially available carbon inks. To demonstrate the suitability of ink in an industrial application, an all‐printed, elastomer‐based force sensor is fabricated. This “pyrrole methodology” is scalable and broadly applicable, laying the foundation for the realization of printed functionalities with improved electromechanical performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.